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Physical modeling of near-Earth Asteroid (29075) 1950 DA |
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| Authors: | Michael W Busch Jon D Giorgini Lance AM Benner Randy Rose Petr Pravec Michael J Ireland Stephen B Broschart Michael C Nolan Jean-Luc Margot |
| Institution: | a Division of Geological and Planetary Sciences, California Institute of Technology, Mail Code 150-21, Pasadena, CA 91125, USA b Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA c Astronomical Institute, Academy of Sciences of the Czech Republic, Fricova 1, CZ-25165 Ond?ejov, Czech Republic d Department of Aerospace Engineering, University of Michigan, 1320 Beal Avenue, Ann Arbor, MI 48109, USA e University of Maine at Farmington, Preble Hall, 173 High St., Farmington, ME 04938, USA f Arecibo Observatory, National Astronomy and Ionosphere Center, HC03 Box 53995, Arecibo, PR 00612, USA g Department of Astronomy, Cornell University, 304 Space Sciences Bldg., Ithaca, NY 14853, USA |
| Abstract: | Near-Earth Asteroid (29075) 1950 DA may closely encounter Earth in 2880. The probability of Earth impact may be as high as 1/300, but the outcome of the encounter depends critically on the physical properties of the asteroid Giorgini et al., 2002. Science 196, 132-136]. We have used Arecibo and Goldstone radar data and optical lightcurves to estimate the shape, spin state, and surface structure of 1950 DA. The data allow two distinct models. One rotates prograde and is roughly spheroidal with mean diameter 1.16±0.12 km. The other rotates retrograde and is oblate and about 30% larger. Both models suggest a nickel-iron or enstatite chondritic composition. Ground-based observations should be able to determine which model is correct within the next several decades. |
| Keywords: | Asteroids composition Asteroids dynamics Asteroids rotation Near-Earth objects Radar observations |
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